1. Field of the Invention
This invention relates to ecological environment monitoring technology, and more particularly, to a wireless sensor network gateway unit with failed link auto-redirecting capability which is designed for integration to a wireless sensor network (WSN) for providing a gateway function with a failed link auto-redirecting capability for the wireless sensor network.
2. Description of Related Art
In agricultural research and management, it is an important task to monitor the ecological environment of a farmland used to cultivate crops such as fruits, rice, and vegetables. The main purpose is to collect a set of ecological data that are considered as vital factors that would significantly affect the cultivation and growth of crops on the farmland. These ecological data include, for example, number of clustered pests (such as fruit flies) per unit area, temperature, humidity, sunlight amount, and wind speed, to name a few. Research personnel can analyze these ecological data for effective management of the farmland to achieve optimized crop production.
Traditionally, the collection of ecological data from farmlands is carried out by human labor work. For example, the number of pests per unit area is collected by firstly using a net to capture a group of pests within a certain area, and then visually counting the total number of pests being captured in the net, and finally using statistical methods to estimate the total number of pests within the entire area. All these works are carried out by human labor. For collection of climate-related ecological data (temperature, humidity, sunlight amount, wind speed, etc.), this task is traditionally carried out by installing temperature sensors, humidity sensors, sunlight amount sensors, wind speed sensors on the farmland; and the sensed data are visually inspected and manually recorded by the research/management personnel. The collected ecological data are then analyzed and compiled by the research personnel into written reports. These written reports are then used as references for management of the farmland to achieve optimized crop production. For example, if the number of pests per unit area is considered to be overly large, pest-killing or expelling means should be provided; if temperature/humidity is too high, conditioning means should be installed; and if the wind speed is too high, wind-shielding means should be installed.
One apparent drawback to the labor-based work for ecological data collection is that it is quite tedious, laborious, and time-consuming for the research/management personnel to carry out. Moreover, if the farmland is located at a remote site, such as a distant mountain or rural place, the research/management personnel might have to spend lots of time and cost in the travel to the farmland.
In view of the aforementioned drawback of the traditional approach for ecological data collection and analysis, there exists a need in the field of agricultural research and management for a system that allows remote and automatic monitoring of the ecological environment of a farmland without requiring the research/management personnel to travel to the farmland or collect the ecological data by human labor.
In the construction of an ecological environment remote monitoring system, wireless sensor network (WSN) and gateway unit are two essential components for front-end implementation of the system. A WSN is composed of a plurality of wireless linked sensor nodes which can transmit data to the gate unit by a multihop routing method. In practical use, however, the failure of one single sensor node in the WSN system would cause all the other sensor nodes that are down-linked to the failed sensor node to suffer from a failed link, thus unable to transfer their sensed ecological data to the gateway unit. In other words, the failure of one single sensor node could affect the overall operational reliability of the WSN system.